Since a fuel cell executing a power generation by a chemical reaction between a hydrogen gas and an air generates heat when executes the power generation, it is necessary that a cooling system circulates a refrigerant such as a coolant to the fuel cell to suppress an increasing of a temperature of the fuel cell.
In the above cooling system, the coolant may be leaked from a circulation passage of the coolant due to a damage of a pipe constituting the circulation passage, the fuel cell may be activated in a state where the increasing of the temperature of the fuel cell cannot be sufficiently suppressed, and the fuel cell may be deteriorated.
According to JP2002-164070A, in a cooling system, a liquid collecting unit is located on a bottom surface of a casing that receives a fuel cell. The cooling system senses a liquid level of the coolant stored in the liquid collecting unit and detects a leakage abnormality of the coolant.